Lasers/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim reads from a typed letter. TIM: Dear Tim and Moby, how do you make a laser? From, KYLE180. Moby standing next to Tim, shoots a laser from his finger onto the letter. The letter burns and falls into pieces. TIM: Whoa. The word "laser" stands for light amplification by stimulated emission of radiation. The words each letter of laser stands for are shown. TIM: You can find lasers all over the place in modern technology. A laser beam is a powerful beam of coherent light. By coherent, I mean that the light emitted from a laser is all of the same wavelength. An image shows a laser beam that is overlaid with equal-sized wavelengths. MOBY: Beep. TIM: You mean you have a laser in your hand and you don't know? All right. Laser light comes from a lasing medium that can be a solid, liquid, or gas. The atoms in the lasing medium are pushed into an excited state by an energy source, like electricity. An animation shows the lasing medium inside of a tube. There are dots in the medium that represent atoms. There are two electrical poles in the tube that give off sparks of energy. TIM: After the atoms have absorbed the energy, they have to release it in the form of a photon, a single unit of energy. When a photon gets loose, it bangs into another atom causing it to release another photon with an identical wavelength. An animation illustrates how energy is created from atoms and photons as Tim describes. TIM: Mirrors at either end of the laser bounce these photons back and forth and back and forth. Pretty soon, a huge collection of coherent light is bouncing around inside the laser An animation shows the mirrors inside the tube and the photons bouncing between them. TIM: One of the mirrors is only half silvered, allowing some of the light to leave the tube in a tight beam of laser light. The animation shows a laser beam coming out of the light. MOBY: Beep? Moby points a flashlight in a dark room. TIM: Well, that's why laser light is so special. A light bulb sends different wavelengths of light out in all directions. All of those different wavelengths, which we see as color, add up to a diffused white light. Laser light is always one color, and highly focused. An animation shows diffused light from a flashlight above a straight line of light from a laser beam. TIM: They can be used for a variety of purposes, from playing music, to communications, to measuring distance, to delicate medical procedures. Images illustrate describes laser hitting a music CD, a satellite beaming a laser down to earth, a laser device measuring the distance of a far-off mountain, and a laser performing a delicate operation. TIM: Some lasers, made from light in the infrared portion of the spectrum, are so hot that they can cut through metal! An animation shows an infrared laser cutting through metal. MOBY: Beep. TIM: Yeah, and lasers are used for a lot of other things you might not have thought of. Like, you can use them to make holograms, those 3-D-looking images. Doctors use them now to permanently treat vision problems in a process called LASIK. And they're used in barcode scanning devices at just about every supermarket and pharmacy! Plus, lasers have become pretty cheap to own so you can even use one to annoy your cat! Images illustrate the laser usages that Tim describes. MOBY: Beep? Moby holds up a laser fencing sword. TIM: I don't know how that thing works. Moby points the swords in different directions. TIM: Oh, please be careful with that. Category:BrainPOP Transcripts Category:BrainPOP Engineering & Technology Transcripts